1. Field of the Invention
This invention relates to a method for preparing polyfluoroalkyl group containing compounds. More particularly, it relates to a method for preparing polyfluoroalkyl group containing esters, or alcohols or mixtures thereof by the following reactions:
R.sub.f CH.sub.2 CH.sub.2 X + RCONR'R" + H.sub.2 O.fwdarw.R.sub.f CH.sub.2 CH.sub.2 OCOR + (NH.sub.2 R'R")X PA1 R.sub.f CH.sub.2 CH.sub.2 OCOR + H.sub.2 O.fwdarw.R.sub.f CH.sub.2 CH.sub.2 OH + RCOOH PA1 R.sub.f CH.sub.2 CH.sub.2 X + RCONR'R" + H.sub.2 O.fwdarw.R.sub.f CH.sub.2 CH.sub.2 OCOR + [R'R"NH.sub.2 ]X PA1 R.sub.f CH.sub.2 CH.sub.2 OCOR + H.sub.2 O.fwdarw.R.sub.f CH.sub.2 CH.sub.2 OH + RCO.sub.2 H
wherein R.sub.f represents perfluoroalkyl groups containing C.sub.1.sub.-23 carbon atoms, R, R' and R" represent hydrogen atoms or lower alkyl groups, and X represents bromine atoms or iodine atoms.
2. Description of the Prior Art
The polyfluoroalkyl halides R.sub.f CH.sub.2 CH.sub.2 X(X = Br or I) are readily available materials. This series of compounds forms a potentially valuable series of intermediates for the synethesis of the corresponding polyfluoroalkyl esters, R.sub.f CH.sub.2 CH.sub.2 OCOR, and polyfluoroalkyl alcohols, R.sub.f CH.sub.2 CH.sub.2 OH, which are useful products, if suitable means could be provided for converting the polyfluoroalkyl halides to the useful products. These polyfluoroalkyl group containing esters and alcohols are, in turn, useful intermediates for the preparation of various useful products such as water and oil repellents, surface active agents, lubricants, and the like.
A method is known for the conversion of these halides to the corresponding esters which involves the reaction of a polyfluoroalkyl halide with silver acetate. The resulting esters are then converted to the corresponding alcohols by hydrolysis. Although the yields are usually not too low, the reaction is slow and the expense of reconverting the silver halide produced to a useful form of silver makes the process uneconomical. Naturally, silver is very expensive so it is necessary to recover it and to reuse it.
U.S. Pat. No. 3,171,861 discloses various processes for the preparation of perfluoroalkyl group containing alcohols. This process has the disadvantages of many reaction steps, severe reaction conditions, low yields of products, and the like. U.S. Pat. No. 3,239,557 discloses another method for converting polyfluoroalkyl halides to the corresponding esters by reacting the halides with alkali metal carboxylates in anhydrous monohydric alcoholic solvents. In this method, olefin by-products having the formula R.sub.f CH =CH.sub.2 are readily formed by dehydrohalogenation of the polyfluoroalkyl halide. Moreover, when the polyfluoroalkyl halides are reacted with an alkali metal hydroxide, the desired polyfluoroalkyl alcohols, R.sub.f CH.sub.2 CH.sub.2 OH, are not obtained because only olefins R.sub.f CH = CH.sub.2 are obtained.
A need, therefore, exists for a method of converting polyfluoroalkyl halides to the corresponding alcohols and esters in high yields without using expensive reagents and without producing appreciable amounts of undesirable by-products.